A. Field of the Invention
The present invention relates to a collated fastener strip and, more particularly, to an improved strip with a carrier or tape capable of detachably mounting a large variety of nails and screws in a more positive manner than before.
B. Description of the Background Art
The commercial success of powered nail and screw driving tools led to the desire for a magazine containing ever larger quantities of fasteners so collated as to avoid the generation of any debris during a fastener driving operation. U.S. Pat. Nos. 3,438,487 and 3,450,255 disclose a flexible plastic tape having an elongated web carrying two parallel rows of spaced tabs along opposite edges. The free ends of the tabs are slotted and terminate in circular openings into spaced pairs of which the shanks of nails are inserted to detachably mount nails on the carrier. U.S. Pat. No. 4,383,608 discloses a carrier with modified tabs and a carrier with only a single row of tabs.
The nails are frictionally retained within the tabs until separated therefrom by contact with a driver blade of a powered nailer. Since the nail carrier, usually in a coiled form, is carried in a magazine on the tool, the nails are subject to forces resulting from the tool operation and handling that tend to dislodge them from the tabs with the result that the nails cannot be properly driven. To avoid this, the diameter of the circular openings in the tabs is made as close as possible to the diameter of the nail shanks. This permits nail insertion without fracturing or distorting the plastic arms defining the slots, while affording as large a frictional force as possible. However, the matching of the diameter of the nail shanks and the tab openings requires a manufacturer to inventory as many different sizes of tape or carrier as there are different nail diameters. In addition, it is difficult to visually distinguish carriers or tapes for nails having diameters that are as similar as 0.086 inch and 0.092 inch, for example.
These flexible plastic tapes or carriers have also been modified for use with threaded fasteners such as screws. As an example, U.S. Pat. No. 3,885,669 discloses such a tape with slotted tabs having a terminating opening whose diameter is proportional to the major and minor thread diameters of, for example, a drywall screw. At times, when the major thread diameter is greater than the diameter of the tab opening and the thread pitch is equal to or greater than the tab material thickness, the thread crest engages the tab edge and provides only point contact. This reduces the area and quantity of frictional engagement between the screw and the tab with the result that the position of the screw on the tab or carrier changes during shipment or handling of the powered screwdriver. This causes problems in both feeding and driving the screws.